The present invention relates to dynamic balance machines, and relates more specifically to an air-jet driven dynamic balance test apparatus for testing the dynamic balance of mini rotors which eliminates the interference of external vibration noise.
A variety of mini motors or rotors are known, and widely used in digitized recorders, video tape players and recorders, laser disc drivers, computer diskdrives, laser printers, etc. In order to obtain a satisfactory quality, a mini motor or motor should be tested for its dynamic balance before use. FIG. 1 illustrates a dynamic balance test apparatus according to the prior art, which comprises two rigid upright supports, on which the axle 11 of the rotor 10 to be tested is supported, a motor drive 16, a coupler 15 which couples the axle 11 of the rotor 10 to be tested to the output shaft of the motor drive, 16, and a vibration detector 14 mounted on each rigid upright support. As the motor drive 16 is started, the vibration detector 14 detects the vibration of the upright support and sends a signal to a micro processor unit for analysis and display. During the operation of the dynamic test apparatus, the motor drive 16 may produce a vibration noise to interfere with the detection of the vibration detector 14. Further, because the vibration detector is mounted on a rigid upright support, it cannot detect a weak vibration signal produced by a very small being tested, i.e., this structure of dynamic balance test apparatus provides low sensitivity.